Purpose. To study the biomechanical performance of various allografts and the effects of endplate treatment on a lumbar corporectomy model. Methods. A modified non-lineal tri-dimensional finite-element model of the lumbar spine was used, to which a set of transpedicular instruments was adapted. By means of a finite-element analysis, modeling was carried out of diaphyseal fragments of the femur, the tibia and the fibula. Four configurations were analyzed: with one femur, with one tibia, with three fibulas and with six fibulas. Four surfaces were evaluated that gave support to the graft according to the resection of the various components. Compression loads of 1,000 N were applied, as well as flexion, extension and rotation of 15 Nm respectively. The stresses and displacements caused were calculated. Results. Full cartilage and subchondral bone resection is the configuration that least disrupts stresses within the adjacent vertebrae whereas the use of fibular fragments causes the greatest disruption. The use of the tibial bone gives rise to an asymmetry in the displacement area because of the shape of the said graft. The femur does not bring about a significant disruption of stresses in the adjacent vertebrae thereby constituting a more physiological construct. Conclusions. Preservation of the endplate's cortical bone does not lead to any biomechanical advantage in the reconstruction of the anterior spine. Femoral allografts are the most appropriate ones to replace the vertebral body, compared with the tibia or the fibula.
|Journal||Revista de Ortopedia y Traumatologia|
|Publication status||Published - 1 Sep 2007|
- Bone allograft
- Finite-element analysis
- Lumbar fusion